1. Field of the Invention
The present invention relates to an apparatus, which is controlled by an electronic control device, for the exposure of additional information into the film plane of a camera.
2. Relevant Prior Art
Such apparatus is known, for example, from U.S. Pat. No. 4,567,478 in photomicroscopes and from the automatic cameras xe2x80x9cWILD MPS48/52xe2x80x9d of the Leica Company. In the photomicroscope according to U.S. Pat. No. 4,567,478, the LCD display for generating the additional information which is to be exposed is arranged within the photo tube of the microscope in front of the cameras. The liquid crystal display is reflected by prisms into the photo ray path. In contrast to this, the automatic camera xe2x80x9cWILD MPS48/52xe2x80x9d has a data back. The exposure of the additional information takes place by means of a display which is illuminated from behind and which is arranged behind the film plane of the camera. Cameras with such data backs are also known, for example, from German Patent DE-Al-2,710,735.
The two first named photomicroscopes have in common that the electronic control device is respectively arranged in an operating panel which is specially constructed for the intended application. If data exposure is to be retrofitted to existing photomicroscopes, it is also necessary, according to U.S. Pat. No. 4,567,478, to retrofit the photo attachment including the electronic control device. And also in the automatic camera xe2x80x9cWILD MPS48/52xe2x80x9d, a retrofitting of the control panel is additionally required for the interchange of the camera.
In the camera of the above mentioned DE-A12,710,735, the whole electronics required for the exposure of the additional information is integrated into the data back itself. The input of the additional information takes place through an input keyboard, which is likewise provided on the data back. A solution of this kind is considered to be very disadvantageous, however, in the case of photomicroscopes, since it is often the case that the data back is not easily accessible to the user of the microscope.
The present invention has as its object an apparatus for the exposure of additional information into a camera, in which the additional information can be easily and conveniently entered, even when used on a photomicroscope. In addition to this, it should also be possible to retrofit existing microscopes which lack corresponding data exposure, at as low as possible a cost.
According to the invention, these objects are achieved by an exposure apparatus being controlled by an electronic control device, wherein the electronic control device is a commercially available computer, for example, a personal computer or a laptop, which has at least one serial or parallel standard interface. The exposure apparatus is directly controlled via the standard interface of the computer, that is to say, without the interposition of a special control panel or a further electronic control device. According to the invention, the input means, for example the keyboard, of the computer itself is used for entering the additional information. The additional information which is entered, and the actual camera setting, for example, the exposure time, can be indicated on the computer monitor. Since the computer keyboard and the monitor can be positioned independently of the microscope, convenient input and checking of the additional information are possible.
Since nowadays. many microscopes are already equipped with a commercial computer for microscope control, or since a computer is in any case available to many microscope users, all that is necessary for the retrofitting of existing microscopes is the retrofitting of the apparatus for the exposure of additional information and the loading of the corresponding control program into the computer. A very inexpensive retrofitting is thus possible in most cases. And even if no commercial computer is available to the user and has to be purchased, the computer can still be used for other purposes, which is not the case when a special control panel provides the electronic control apparatus for the camera.
It has been found to be advantageous for programming the program when the parallel printer interface of the computer is used for the control of the data exposure. The conversion which is then required of the parallel interface into the serial I2C interface for the driver of the display used for data exposure can then take place by means of a simple circuit with two transistors.
A particularly simple retrofitting of the apparatus according to the invention is possible when the exposure apparatus is arranged in the data back of a camera. In this case, the camera itself can remain unaltered, and it is only necessary to retrofit the data back. A liquid crystal display can be arranged in the data back in a known manner for the generation of the additional information. To assure that the exposure of the additional information can take place in the short time between the closing of the camera shutter and the film transport, a very bright light-emitting diode should be provided for illuminating the liquid crystal display.
In a further advantageous embodiment of such a data back, two plane mirrors are arranged one behind the other between the light emitting diode and the liquid crystal display, without the interposition of refracting optics, the surface normal of the second mirror being directed at an inclination to the plane spanned by the surface normal of the first mirror and the light emitting diode. It has then surprisingly been found that even LCD displays with dimensions of about 5 mmxc3x9720 mm are illuminated sufficiently evenly by a single light emitting diode, when the light from the light emitting diode is passed via two mirrors arranged in a mutually crossed position. Such an LCD display can have, for example, two columns each with eight fields of a 5xc3x977 dot matrix, so that a total of 16 alphanumeric characters can be represented. In such a two-column liquid crystal display, an insertable screen can be provided between the film and the display. One LCD column can be covered by this screen, so that the user can choose between exposure of additional data within a single column and within two columns.
The device according to the invention can in particular be advantageously used in connection with photomicroscopes. The photomicroscope can itself have additional means for outputting information concerning the microscope setting. It is then advantageous if this means for outputting information is likewise controlled by the computer via the same standard interface as the exposure apparatus. Thus only a single interface of the computer is taken up for both purposes.
The means for outputting information can in particular be the code transducer of the revolving nosepiece and/or the path measurement system of the zoom system of the microscope. In this case, the imaging scale of the microscope image on the camera can be automatically determined by the computer and can be exposed into the picture via the LCD display.
In photomicroscopes with several photo outlets, the cameras can futhermore have a coding in the region where they are attached to the photomicrosope and the photo outlet of the photomicrosope can have an associated counter-coding or a corresponding code reader. If this signal is also read out by the computer, it can be automatically checked by the computer program to determine whether data exposure is all possible in the camera in use, and in the negative case a warning signal can be emitted to the user.